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[Federal Register Volume 89, Number 248 (Friday, December 27, 2024)]
[Proposed Rules]
[Pages 105483-105485]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-30785]

========================================================================
Proposed Rules
                                                Federal Register
________________________________________________________________________

This section of the FEDERAL REGISTER contains notices to the public of 
the proposed issuance of rules and regulations. The purpose of these 
notices is to give interested persons an opportunity to participate in 
the rule making prior to the adoption of the final rules.

========================================================================


Federal Register / Vol. 89 , No. 248 / Friday, December 27, 2024 / 
Proposed Rules

[[Page 105483]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-2712; Project Identifier AD-2024-00145-E]
RIN 2120-AA64

Airworthiness Directives; General Electric Company Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain General Electric Company (GE) Model CF34-8C1, CF34-8C5, 
CF34-8C5A1, CF34-8C5A2, CF34-8C5A3, CF34-8C5B1, CF34-8E2, CF34-8E2A1, 
CF34-8E5, CF34-8E5A1, CF34-8E5A2, CF34-8E6, and CF34-8E6A1 engines. 
This proposed AD was prompted by a predicted reduction in the cyclic 
life of the combustion chamber assembly (CCA) forward flange. This 
proposed AD would require fluorescent penetrant inspections (FPIs) of 
the CCA for any indications and replacement if necessary. The FAA is 
proposing this AD to address the unsafe condition on these products.

DATES: The FAA must receive comments on this proposed AD by February 
10, 2025.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to regulations.gov. Follow 
the instructions for submitting comments.
     Fax: (202) 493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE, Washington, DC 20590.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2024-2712; or in person at Docket Operations between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD 
docket contains this NPRM, any comments received, and other 
information. The street address for Docket Operations is listed above.

FOR FURTHER INFORMATION CONTACT: Alexei Marqueen, Aviation Safety 
Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: 
(781) 238-7178; email: [email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under the ADDRESSES section. Include ``Docket No. FAA-2024-2712; 
Project Identifier AD-2024-00145-E'' at the beginning of your comments. 
The most helpful comments reference a specific portion of the proposal, 
explain the reason for any recommended change, and include supporting 
data. The FAA will consider all comments received by the closing date 
and may revise this proposal because of those comments.
    Except for Confidential Business Information (CBI) as described in 
the following paragraph, and other information as described in 14 CFR 
11.35, the FAA will post all comments received, without change, to 
regulations.gov, including any personal information you provide. The 
agency will also post a report summarizing each substantive verbal 
contact received about this NPRM.

Confidential Business Information

    CBI is commercial or financial information that is both customarily 
and actually treated as private by its owner. Under the Freedom of 
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public 
disclosure. If your comments responsive to this NPRM contain commercial 
or financial information that is customarily treated as private, that 
you actually treat as private, and that is relevant or responsive to 
this NPRM, it is important that you clearly designate the submitted 
comments as CBI. Please mark each page of your submission containing 
CBI as ``PROPIN.'' The FAA will treat such marked submissions as 
confidential under the FOIA, and they will not be placed in the public 
docket of this NPRM. Submissions containing CBI should be sent to 
Alexei Marqueen, Aviation Safety Engineer, FAA, 2200 South 216th 
Street, Des Moines, WA 98198. Any commentary that the FAA receives 
which is not specifically designated as CBI will be placed in the 
public docket for this rulemaking.

Background

    The FAA received a report from the manufacturer that an analysis 
was conducted during a ream repair of the aft flange bolt hole of the 
high-pressure compressor. The analysis determined that the cyclic life 
of the CCA forward flange bolt holes adjacent to the compressor case 
horizontal split line is lower than the current certified limit. This 
condition, if not addressed, could result in failure of the CCA before 
reaching the published life limit, uncontained release of the CCA, 
damage to the engine, and damage to the airplane.

FAA's Determination

    The FAA is issuing this NPRM after determining that the unsafe 
condition described previously is likely to exist or develop on other 
products of the same type design.

Proposed AD Requirements in This NPRM

    This proposed AD would require FPIs of the CCA forward flange for 
any indications and replacement as applicable.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 2,988 engines installed on airplanes of U.S. registry.
    The FAA estimates the following costs to comply with this proposed 
AD:

[[Page 105484]]

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
FPI the CCA forward flange............  8 work-hours x $85 per                $0            $680      $2,031,840
                                         hour = $680.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates an average CCA utilization of 2,143 part cycles 
per year. Based on this life estimate, the FAA is providing an 
estimated annual cost to replace these parts. The FAA estimates that 
369 affected engines will require CCA replacement at 28,500 part cycles 
since new (PCSN), 855 affected engines will require CCA replacement at 
25,500 PCSN, and 1,764 affected engines will require CCA replacement at 
40,000 PCSN. The following summarizes the costs of the proposed AD over 
the analysis timeframe, for the 12 years spanning 2024-2036. The cost 
of early CCA removals, required by this proposed AD, analyzed over 2024 
through 2036, are $265 million at a 2% financial discount rate.

----------------------------------------------------------------------------------------------------------------
                                                                                                   Cost on U.S.
                                                                                     Cost per        operators
                Action                         Labor cost           Parts cost        product     annualized (2%
                                                                                                  discount rate)
----------------------------------------------------------------------------------------------------------------
Replace the CCA (prorated part cost)..  8 work-hours x $85 per          $646,900        $647,580     $24,544,532
                                         hour = $680.
----------------------------------------------------------------------------------------------------------------

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. Subtitle VII: Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    The FAA is issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701: General requirements. 
Under that section, Congress charges the FAA with promoting safe flight 
of civil aircraft in air commerce by prescribing regulations for 
practices, methods, and procedures the Administrator finds necessary 
for safety in air commerce. This regulation is within the scope of that 
authority because it addresses an unsafe condition that is likely to 
exist or develop on products identified in this rulemaking action.

Regulatory Findings

    The FAA determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would not 
have a substantial direct effect on the States, on the relationship 
between the national government and the States, or on the distribution 
of power and responsibilities among the various levels of government.
    For the reasons discussed above, I certify this proposed 
regulation:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Would not affect intrastate aviation in Alaska, and
    (3) Would not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701.

Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

General Electric Company: Docket No. FAA-2024-2712; Project 
Identifier AD-2024-00145-E.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by February 10, 2025.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to the following General Electric Company (GE) 
Model engines:
    (1) CF34-8C1, CF34-8C5, CF34-8C5A1, CF34-8C5A2, CF34-8C5A3, and 
CF34-8C5B1 engines with an installed combustion chamber assembly 
(CCA) having part number (P/N) 4145T11G08, 4145T11G10, 4180T27G02, 
4180T27G04, or 4923T82G02; and
    (2) CF34-8E2, CF34-8E2A1, CF34-8E5, CF34-8E5A1, CF34-8E5A2, 
CF34-8E6, and CF34-8E6A1 engines with an installed CCA having P/N 
4145T11G08, 4145T11G09, 4180T27G01, or 4180T27G03.

(d) Subject

    Joint Aircraft System Component (JASC) Code 7240, Turbine Engine 
Combustion Section.

(e) Unsafe Condition

    This AD was prompted by a predicted reduction in the cyclic life 
of the CCA forward flange. The FAA is issuing this AD to prevent 
failure of the CCA. The unsafe condition, if not addressed, could 
result in failure of the CCA before reaching the published life 
limit, uncontained release of the CCA, damage to the engine, and 
damage to the airplane.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Required Actions

    (1) For affected Group 1 engines with an installed CCA having 
less than 15,000 part cycles since new (PCSN) as of the effective 
date of this AD, before the accumulation of 28,500 PCSN, remove the 
CCA from service and replace with P/N 4180T27G08 or a later approved 
P/N.
    (2) For affected Group 2 engines with an installed CCA having 
less than 15,000 PCSN as of the effective date of this AD, before 
the accumulation of 25,500 PCSN, remove the CCA from service and 
replace with P/N 4180T27G07 or a later approved P/N.
    (3) For affected Group 1 and 2 engines with an installed CCA 
having between 15,000 PCSN and 24,999 PCSN as of the effective date 
of this AD, before the accumulation of 25,000 PCSN, perform a 
fluorescent penetrant inspection (FPI) on the forward flange of the 
CCA for any indications.

[[Page 105485]]

    (4) If no indications are found during the FPI required by 
paragraph (g)(3) of this AD, within 15,000 part cycles from the date 
of the FPI, remove the CCA from service and replace with P/N 
4180T27G07, 4180T27G08, or a later approved P/N, as applicable.
    (5) For affected Group 1 and 2 engines with an installed CCA 
having more than 25,000 PCSN as of the effective date of this AD, at 
the next engine shop visit after the effective date of this AD, 
perform an FPI on the forward flange of the CCA for any indications.
    (6) If no indications are found during the FPI required by 
paragraph (g)(5) of this AD, within 15,000 part cycles from the date 
of the FPI and not to exceed 41,100 PCSN, remove the CCA from 
service and replace with P/N 4180T27G07, 4180T27G08, or a later 
approved P/N, as applicable.
    (7) If an indication is found during any FPI required by 
paragraph (g)(3) or (5) of this AD, before further flight, remove 
the CCA from service and replace with P/N 4180T27G07, P/N 
4180T27G08, or a later approved P/N, as applicable.

(h) Definitions

    For the purpose of this AD:
    (1) ``Group 1 engines'' are GE Model CF34-8C1, CF34-8C5, CF34-
8C5A1, CF34-8C5A2, CF34-8C5A3, and CF34-8C5B1 engines.
    (2) ``Group 2 engines'' are GE Model CF34-8E2, CF34-8E2A1, CF34-
8E5, CF34-8E5A1, CF34-8E5A2, CF34-8E6, and CF34-8E6A1 engines.
    (3) An ``engine shop visit'' is the induction of an engine into 
the shop for maintenance involving the separation of major mating 
engine case flanges, except for the following situations, which do 
not constitute an engine shop visit:
    (i) Separation of engine flanges solely for the purposes of 
transportation of the engine without subsequent maintenance.
    (ii) Separation of engine flanges solely for the purposes of 
replacing the fan or propulsor without subsequent maintenance.

(i) Installation Prohibition

    After the effective date of this AD, do not reinstall any CCAs 
that were removed as a result of paragraphs (g)(1), (2), (4), (6), 
and (7) of this AD in any engine.

(j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, AIR-520 Continued Operational Safety Branch, 
FAA, has the authority to approve AMOCs for this AD, if requested 
using the procedures found in 14 CFR 39.19. In accordance with 14 
CFR 39.19, send your request to your principal inspector or local 
Flight Standards District Office, as appropriate. If sending 
information directly to the manager of the AIR-520 Continued 
Operational Safety Branch, send it to the attention of the person 
identified in paragraph (k) of this AD and email to: [email protected].
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.

(k) Additional Information

    For more information about this AD, contact Alexei Marqueen, 
Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, 
WA 98198; phone: (781) 238-7178; email: [email protected].

(l) Material Incorporated by Reference

    None.

    Issued on December 19, 2024.
Suzanne Masterson,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification ervice.
[FR Doc. 2024-30785 Filed 12-26-24; 8:45 am]
BILLING CODE 4910-13-P
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